# Copyright 2022 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# This is a multi-stage Dockerfile. 
# 1st stage builds the app in the target platform
# 2nd stage create a lean image coping the binary from the 1st stage

#
# Build: 1st stage
#
FROM golang:1.24-alpine as builder 
ARG BUILDPLATFORM    
ARG TARGETPLATFORM
RUN echo "I am running on $BUILDPLATFORM, building for $TARGETPLATFORM"  
WORKDIR /app
COPY go.mod .
COPY hello.go .
RUN go build -o /hello && \
    apk add --update --no-cache file && \
    file /hello   

#
# Release: 2nd stage
#
FROM alpine
WORKDIR /
COPY --from=builder /hello /hello
CMD [ "/hello" ]